In recent years the world's wind power development is very rapid, its capacity to 30% annual rate of increase. In 1998, the installed capacity of wind power in the world was 9839MW, an increase of 29.6% over 1997. April 1999 the world wind power installed capacity has exceeded 10000MW. At present, the main regulating technologies for wind turbines in the world market include: regulation of wind turbine technology with pitch control, wind turbine technology with variable pitch control, regulation of pitch regulation initiatively and four kinds of variable speed constant frequency transmission. As the onshore wind turbines are limited by the conditions of transportation and installation, the stand-alone capacity of 2MW is the limit for the development of wind turbines. This is mainly because the blade length will reach 60-70m after the wind turbine capacity reaches 2MW and the transportation on land is extremely difficult. Of the crane capacity will exceed 1200-1400t. This capacity crane, in addition to Europe and the United States and other developed areas, the rest of the region basically no. In the meantime, in the developed regions such as Western Europe, where the population is relatively dense, the location where wind turbines are installed is greatly restricted, and people will vigorously develop offshore wind farms. At present, our country only masters the technology of pitch-regulated stall-type wind turbines. The capacity of such wind turbines can be expanded to 750kW, and the other three technologies are not involved. China's wind turbine technology development is still at a low level.
The current world market, the main wind turbine conditioning technology
1, home pitch regulation wind motor technology (Stallregulation)
This technique is at the heart of what is known as a typical Danish wind power technology, whose basic principle is to utilize the stall characteristics of the blade airfoil itself. Its advantages are: regulation is simple and reliable, control can be greatly simplified; its disadvantages are: paddle, wheels, towers and other major force components increased stress.
Now the international 600kW F unit, most still using the technology, such as MFG-MICON, BONUS, NORDEX and other famous manufacturers have adopted the technology.
2, pitch regulation wind motor technology (Pitegulation)
The main representative is Vestas.
The main advantages of pitch adjustment are: the paddle force is smaller, the blades can be made lighter and the structural components of the wind turbine can be made lighter; the disadvantage is that the structure is complex.
3, take the initiative to pitch adjustment technology (Activestallregulation)
This method of adjustment is a combination of the two methods described above. At present, several wind turbine manufacturers in the world, such as MFGMICON and BONUS, adopt this kind of technology in wind turbines larger than 600kW. The main benefits of this method of adjustment are: the characteristics of a constant pitch adjustment method, a small change in output power, and a smooth wheel.
4, variable speed constant frequency (Viarablespeed)
This method of adjustment is theoretically the most optimal method of adjustment. The manufacturers currently using this technology are mainly Enercon in Germany and Largeway in the Netherlands.
This method of regulation allows for maximum efficiency before the output power drops below the rated power. However, when the output power is greater than the rated power, that is, the wind speed is greater than the rated wind speed, the adjustment method is the same as the pitch control method. Constant-frequency devices are expensive and are the reason this technology is only used heavily in Germany, but rarely in other countries.
The current world trend of wind turbine technology development
Due to the limitations of onshore wind turbines due to transportation and installation, the stand-alone capacity of 2MW is the limit for the development of wind turbines. This is mainly because blades reach 60-70m in length after reaching 2MW in wind turbines and are extremely difficult to transport on land. Installation Crane capacity will exceed 1200-1400t. This capacity of the crane, in addition to Europe and the United States and other developed areas (only a limited number), the rest of the region basically no. In the meantime, in the developed regions such as Western Europe, where the population is relatively dense, the location where wind turbines are installed is greatly restricted, and people naturally look at the offshore wind farms. In order to adapt to the development of offshore wind farms, the EU published a white paper on energy from 2000-2010 in Amsterdam in June 1999, in which a wind power generator with a capacity of 3-5 MW is to be developed as one of its priorities.
Many European universities, research institutes and manufacturers have introduced a variety of new concepts of offshore wind turbines. One of the most widely-watched wind turbines is the wind turbine with the following technologies: 3 blades, downwind; no gearbox; multi-pole generator with wind Round straight; airfoil tower (wind tower); steering system at the bottom of the tower; variable speed constant frequency.
The main features of 3-5MW offshore wind turbines are as follows: The transportation problem can be directly transported by sea (the factory is located by the sea), and can be solved by large-capacity sea-going floating crane during installation. Large floating capacity of the sea, more than 1500t floating crane is more common.
In general, the cost of onshore wind farms is about 70% for wind turbines and about 30% for infrastructure (basic grids, roads, etc.). The cost of offshore wind farms is about 30% of that of wind turbines, with about 70% of infrastructure (basic, submarine cables, etc.). However, due to good wind resources, offshore wind farms can generate 50% more electricity per year than onshore wind farms. At the same time, due to the adoption of the above new technologies, large-capacity offshore wind turbines have been reduced in cost, increased in operational reliability and reduced in operating costs, so that the cost of generating electricity can be equal to or lower than that of onshore wind farms.